Header/Exhaust Feedback

Ok I have read the articles on long tube and short tube headers. I have decided on long tubes, the most bang for my buck I believe is going to be PaceSetter 70-2267's, would like to get kook's but don't have that kind of cash. When I do the header install I plan on changing my Cats out to Magnaflow 99006HM Universal Cat's. Where I need the feedback is on the whether I should install a Y pipe, run true dual out, run an X Pipe? When I start this project I am looking for the best sound and HP Gain. I know that vehicles require some back pressure and I don't want to do all this work and loose HP. I plan on doing most of the work myself except for the welds. Also, what else would anyone recommend as far as the exhaust, true dual or dual in and dual out exhaust?

I've been very happy with a dual-in/dual-out solution from Magnaflow. One muffler distributes the pressures, and I found immediate differences in low end torque increases (positive) over the previous setup (which was basically straight piped with some crap-tastic glass-packs). It eliminated the need to decide on an X/Y setup, and has the added value of not crapping out on me when I buried the passenger side pipe in a hill during a mountain excursion. Flow just ported to the other side.

You're also likely to lose some low end torque with headers. Your high end HP will jump a bit (and the associated DYNO numbers), but be sure you're not doing it for "off the line" power. It may not be there if you don't have the back pressure to keep the exhaust gasses flowing properly out of the engine at the lower RPMs. It's always a tricky balance when adding headers... Me? I prefer the low end torque. I rarely drive constantly at the 4000+ RPM range, which is where the headers really shine.

agreed, although the power gain was more likely due to the more free flowing muffler, but you will loose alittle low end with the long tubes but you can make up with it with gears or a stall. and then some and have it rip up top

All good advice added above, only thing I can add is make sure you use some kind of locking header bolts to mount them to the engine. Unless you like tightening them all the time, mine have a 3/4" flange and I'm using Stage 8 locking bolts and haven't had to tighten them in the two years I've had them on.

Next week I am taking my truck to have the exhaust done, I am running Doug Thorley Tri Y long tubes, reducer into 3" pipe, magnaflow cats, "X" pipe, 2 SLP loudmouth 2 mufflers, side exit behind rear tires. 3" true duals all the way back, next will be close to 600hp so I'm planning ahead lol!!